The average daily price for Alaskan itineraries varies dramatically depending on when you sail, which ship and grade of cabin you choose, and when you book. A mainstream cruise on a large ship in Alaska doesn't usually cost much more than a Caribbean cruise. A luxury cruise can cost three times as much as a mainstream cruise, but these cruises will be more all-inclusive in terms of complimentary beverages and specialty dining on board. Cruises on small adventure vessels tend to be pricier than trips on mainstream lines because there are fewer passengers to cover the fixed costs of the cruise. When you sail will also affect your costs: published brochure rates are highest during July and August; you'll pay less, and have more space on ship and ashore, if you sail in May, June, or September.